The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.
Blowouts of wells (also referred to us kicks) may lead to catastrophic events. An example of such an event is the British Petroleum's environmental catastrophe that occurred in 20 Apr. 2010.
A well blowout is an uncontrolled release of hydrocarbons from a well. Typically, blowouts occur after a failure of the pressure control systems contained in the well.
Currently, wells include Blowout preventers (BOP) to avoid blowouts. A BOP controls the pressure within the well and the flow of hydrocarbon as well as avoids tools and drilling parts from being ejected out of the wells.
It is essential that routine testing be undertaken of the interior of the well and, in particular, of the BOP. For example, the BOP includes shears and packing seals that may be caked with debris such as mud, cement or metallic residue. This may render the BOP inoperative. Regular inspection and cleaning of these seals is essential to ensure proper functioning of the BOP.
The routine testing includes a visual inspection of the equipment included in the well and, in particular, of the BOP. One of the reasons that visual inspection is undertaken is to be able to visualise the location and configuration of the debris. Visualising the location of the debris and its configuration permits applying a cleaning process at the particular location where the debris is located. This makes the cleaning process more efficient.
A particular disadvantage of conventional survey tools is that the inspection and cleaning process using these conventional tools is cumbersome and time consuming. This is particularly true because the process requires use a multitude of drill string tools that need to deployed into the well separately. As an example, typically, at first instance a jet cleaning tool is deployed into the riser. This tool cleans the interior of the well and in particular the BOP. After completion of this particular cleaning process, the jet cleaning tool is removed from the well and a conventional downhole camera is inserted into the well for inspection of the interior of the well and its equipment.
Unfortunately, on many occasions, the cleaning process, conducted by the cleaning tool, might not have properly removed all the debris; under these circumstances, the interior of the well needs to be further cleaned using the jet cleaning tool. For this, the survey tool needs to be pulled out of the well for redeployment of the cleaning tool into the well for further cleaning of the well. This adds additional costs to the drilling campaign.
Currently, there are survey tools that incorporate an outlet for discharging cleaning fluid into the well. This allows some portion of the debris to be removed before inspection of the interior of the well and of the equipment located in the well.
However, the discharging of the fluid is not sufficient for properly cleaning the interior of the well and the equipment located therein. Currently, proper cleaning can only conducted using a jet cleaning tool.
It is against this background that the present invention has been developed.